LC Project Progress

Project Overview

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Project Aim

The main aim is to study the properties of the Higgs particle and W W fusion in electron-positron collisions at a linear collider. The project will focus on the direct reconstruction of the H → b bbar decay mode, as this has the highest branching ratio for a Higgs of mass around 120 GeV as discovered at CERN.

Project Interim Report

Invariant Mass of Higgs (MC simulated events)

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Determined the invariant mass of the reconstructed Higgs boson in the MC simulated events from its two b jets, and its two c jets (from the decay mode of H → c cbar). Suitable Gaussian fits were applied to the invariant mass distributions to find the peak for these decay modes, with suitable errors quantified.

Attached plots:

H → b bbar with Gaussian fit

H → c cbar with Gaussian fit

Project Plan

The aim is to now implement a neural network flavour tagging processor to separate background and signal events, and to find how well the reconstructed particles compare with the “true” underlying particles. I will move on to look at the WW fusion process at a higher centre-of-mass energy and aim to construct a full Higgs cross-section analysis.

Steps:

• Reconstruct H->bb using truth tagging in ZH
• Implement "real" b-tagging and do the same
• Switch to WW fusion and find the H->bb peak there
• Make a WW->H->bb cross-section measurement

Useful Links

• Light Higgs Production and Decays to Pairs of Bottom and Charm Quarks at 3 TeV